As the popularity of transmitting information over the telephone lines has grown, the need for devices to couple apparatus to and from the telephone transmission lines has also grown. While it is possible to electrically couple information sources and sinks to the telephone lines, in many states that access is prohibited or limited by regulation, and, in any event, a much simpler coupling arrangement is available. Thus, the popularity of acoustic couplers, employing a conventional telephone handset, has by far become the most popular method of coupling information to and from the telephone lines.
Indeed, many information handling devices are manufactured which include an acoustic coupler so that information may be coupled from or to the device and the telephone lines by simply inserting a conventional telephone handset into the acoustic coupler. While these prior art devices work quite well in their intended environment, there is a need for improvement.
A major problem is the space taken up by the acoustic coupler. With the advent of LSI devices and the commensurate shrinkage of the data source or sink, the space required by the acoustic coupler has become embarrassingly large. Indeed, in some cases, the acoustic coupler takes up a larger space than that occupied by the data source or sink.
Davis, in U.S. Pat. No. 3,992,583 has attempted to overcome this problem by providing an acoustic coupler which protrudes from the associated data source/sink.
The Davis arrangement minimizes the effect of coupler volume by locating the coupler exterior to the electronics package. This is only a partial solution and when the Davis coupler is not in use its size may overshadow the size of the electronics package. Furthermore, the information source/sink with which the Davis acoustic coupler is connected, is relatively larger than the acoustic coupler itself. In other applications, for example, in a hand-held data storage device, the volume penalty required by employing the Davis type coupler would be excessive.
Therefore, it is an object of the invention to provide an acoustic coupler which is a stand alone device, connected to a data source or sink only by electrical connections. It is another object of the invention to provide such a coupler which, while being an integral molded component, can be folded or compacted when the coupler is not in use. It is another object of the present invention to provide an acoustic coupler having a relatively conventional configuration when in use, i.e., including a pair of muffs joined together but which provides a flexible joint so that the coupler can be folded on itself to thereby reduce the space occupied by the coupler when not in use. It is still another object of the invention to provide such a coupler which may include active elements, for example, a preamplifier, so that the length of an electrical connection, and shielding thereof, between the acoustic coupler and a data source/sink is not critical. Other objects and advantages of the invention will appear from the following description.